As is well known by skilled persons in this field, slab tracks, or tracks on a slab of concrete, are a type of railway track that sits on concrete or asphalt beds, these materials replacing the conventional ballast. The criteria for their construction are much more demanding than those of traditional track, as they require greater precision in so far as refers to the levelling, alignment and track width, as any subsequent correction of possible mistakes is very expensive. Along these lines, it is particularly important to provide effective drainage so as to eliminate possible future maintenance problems, as in traditional tracks it is the ballast that guarantees this drainage function.
Slab tracks have the disadvantage compared to traditional tracks, that the construction cost is higher than for the latter, but on the other hand, they have a series of significant advantages compared to traditional tracks, from various points of view: On one hand, they guarantee the correct positioning of each one of the elements that make up the track, such as the rails and sleepers, keeping the geometric parameters unchanged over time, and on the other hand, require less maintenance work than traditional tracks, with a reduction which according to some estimates is in the order of some 20% less, which thus allows the intervention times to be reduced and, consequently, increases the operating availability of the infrastructure.
In addition, slab tracks also have some other positive aspects amongst which the following can be mentioned as examples: greater safety and reliability of their performance and repair in case of derailments, which in turn are less probable owing to the fact that slab tracks have two defences: One active, that reduces the formation of transversal defects, which translates into greater train stability, and another that is passive, based on its robustness, which makes it more solid from a structural point of view.
In accordance with the known methods of construction, the slab track can either have embedded rails, that is, the rail is introduced onto the inside of a channel made in the concrete slab, in such a way that the rail is supported along its entire length with the resulting reduction of stress and a better distribution of the loads, both static and dynamic, or with the rail assembled on sleepers. In whichever case, the parts that can be highlighted on a slab track are as follows:                Main slab: Is made up of concrete and the rails are fastened onto it.        Elastomeric product: This is a rubber based product that is placed between the rail and the main slab, in such a way that the assembly made up of the main slab and the elastomer perform functions equivalent to those of the ballast and the sleepers on conventional tracks.        Base slab: Located between the main slab and the platform, its object is to distribute the pressures equally on the platform and are usually some 15 centimeters in thickness.        Platform: Conceived and carried out in such a way as to provide good drainage capacity:        Sleepers: As has been said, they are only used in some types of slab tracks, and        Rail: Of the same type as in conventional tracks, but with reduced cross section.        
The above is a summarised exposition of the differing components that are used in the construction of a slab track, together with some performance characteristics of same.
Given the high number of advantages gained from the installation of slab tracks compared to conventional tracks on ballast, it is desirable to be able to have the methods available that allow the assembly to be used in those cases in which its use is advisable, or which are suitable for whatever circumstance. This present invention has been developed taking the above need into consideration, and to that end is aimed at providing an installation method for slab tracks on the inside of tunnels that improves the traditional methods, where the space available is much more limited than on open land, and because of this a process sequence has been developed by means of which solutions are provided for the differing construction phases. This sequence of process stages constitutes the essence of the invention method, and is going to be described in greater detail below: